Ability to email specific shifts to volunteers

I manage 300 volunteers in our food pantry, ranging in age from 20 to 80. Some volunteers work only one shift, so I was hoping to find a way to email them a specific, recurring shift, such as bagging produce every Monday from 10 to 12 p.m. I think it would be helpful for technologically challenged volunteers as well to received targeted shifts, rather than log in to find 20 shifts they have never worked.